Feasibility of Ballistic Strength Training in Subacute Stroke: A Randomized, Controlled, Assessor-Blinded Pilot Study

Objective: To establish the feasibility and effectiveness of a six week ballistic strength training protocol in people with stroke.Design: Randomized, controlled, assessor-blinded study. Setting: Sub-acute inpatient rehabilitation. Participants: Consecutively admitted inpatients with a primary diagnosis of first ever stroke with lower limb weakness, functional ambulation category score of ≥3, and ability to walk ≥14m were screened for eligibility to recruit 30 participants for randomization. Interventions: Participants were randomized to standard therapy or ballistic strength training three times per week for six weeks. Main outcome measures: The primary aim was to evaluate feasibility and outcomes included recruitment rate, participant retention and attrition, feasibility of the exercise protocol, therapist burden and participant safety. Secondary outcomes included measures of mobility, lower limb muscle strength, muscle power and quality of life. Results: Thirty participants (11% of those screened) with mean age of 50 (SD 18) years were randomized. The median number of sessions attended was 15/18 and 17/18 for the ballistic and control groups respectively. Earlier than expected discharge home (n=4) and illness (n=7) were the most common reasons for non-attendance. Participants performed the exercises safely, with no study-related adverse events. There were significant (p<0.05) between-group changes favoring the ballistic group for comfortable gait velocity (mean difference (MD) 0.31m/s, 95% confidence interval CI: 0.08 to 0.52), muscle power, as measured by peak jump height (MD 8cm, 95% CI: 3 to 13) and peak propulsive velocity (MD 64cm/s, 95% CI: 17 to 112). Conclusions: Ballistic training was safe and feasible in select ambulant people with stroke. Similar rates of retention and attrition suggest that ballistic training was acceptable to patients. Secondary outcomes provide promising results that warrant further investigation in a larger trial.